Printing machines, such as rotary offset lithographic duplicating machines, rotary printing presses, or the like, normally include a printing couple which includes a number of cylinders and/or rollers such as impression cylinders, master cylinders, blanket cylinders, ductor rollers, regulator rollers, and the like. An ink fountain is disposed on the machine, usually at the rear thereof, for feeding ink to the various rollers of the printing couple which transfers images to copy sheets.
Conventional ink fountain assemblies normally take the form of a fountain trough defined by an elongated blade extending along one side and an ink fountain roller extending along the opposite side of the trough. The ink fountain roller transfers the ink to the other rollers of the printing couple. The blade is adjustable by a plurality of thumb screws spaced longitudinally of the blade to vary a "gap" between an edge of the blade and the ink fountain roller in order to maintain consistency in the amount of ink applied to the roller uniformly along the length of the roller and to adjust the ink fountain "setting" for any given printing job. The thumb screws are individually rotatably adjustable, i.e. independently of each other, and usually have an inner distal end which moves against the underside of the blade to move the blade toward and away from the roller and, thereby, vary the gap.
The normal procedure of setting an ink fountain, i.e., the flow of ink through the gap, is a trial and error method. Specifically, a job copy is inspected and all of the adjustable thumb screws are set by sheer estimation. A number of trial copies are run on the machine and the results are observed. The thumb screws are adjusted for too little or too much ink being fed through the gap in the area of each screw. Another trial run is performed, and the procedure is repeated until an acceptable copy is made, taking into consideration proper ink coverage, color density, resolution, ink film thickness and ink drying time. Densitometers or other instruments may be used during the procedure. In actual practice, a very experienced machine operator becomes very proficient with these procedures. However, less experienced operators cause cost effectiveness problems, and beginner or trainee operators often have extraordinary problems in attaining acceptable copies.
The above scenario results in further inefficiency problems, even with an experienced machine operator, because of the inability of efficiently duplicating a precise ink fountain "setting" once the setting is changed either intentionally or inadvertently. For instance, a printing run or job of 10,000 sheets may be on order. Once the job is finished, another job is started, with the thumb screws adjusted to a completely different fountain setting. Thereafter, whether a day later or months later, if an order for the previous job must be repeated, there is no way to duplicate the paper ink fountain setting without again following the usual trial and error procedure. Such periodic or repeat orders are quite common in the print shop business.
In addition, should any one or more of the thumb screws be rotated out of their proper position of adjustment, either accidentally or through tampering, there is no way to detect that the thumb screws are out of adjustment.
The above problems easily can be visualized when considering that the thumb screws simply have knurled heads for manually adjustably rotating the screws. In some instances the screws have diametral slots in the outer face of the heads for receiving a tool, such as a screwdriver, for rotatably adjusting the screws. In any event, one thumb screw usually is rotated, in its proper position of adjustment, to a different angle than its adjacent or other screws. Therefore, even if the heads have a tool-receiving slot, the slots may appear in all kinds of angular orientations. There is no way to repeat at a later time all of the respective angular positions of the screws, and there is no way to detect whether or not any of the screws have been unintentionally rotated away from the positions in which they were initially rotated to proper adjustment.
There are various known, sophisticated scanning mechanisms used in high priced presses for setting ink fountain screws by servo-motors or similar devices and which can be repeatable. The mechanisms are computerized and feed back signals from the scanners to the ink fountain screws. However, such mechanisms can cost almost as much as an entire print shop machine.
This invention is directed to solving the above problems by providing a unique system including a visual calibrated system of setting an ink fountain and including indicating means removably mountable on each thumb screw for facilitating repeat setting of the ink fountain and for detecting any movement of the thumb screws away from their proper positions of adjustment.